[Refactoring] Javascript: whitepaces + indentation + if-else
[Refactoring] Javascript: if-else
Removed unreachable code
Annotated private functions
Moved processPendingRequests() to EOF
Renamed proxy

The naming now reflects, that the proxy is only being used for images.
[Refactoring] JS code style
Removed unused code
Removed unused `requestsPending['token']`
Switch from clearState() to initState()
Code style: whitespace
Renamed updateConfig() to getConfig()
Removed unused code
Added missing callback
Removed unused function isEmpty()

Was introduced in commit 49875713dccbcf8d5c1e179db6108f101a2be0c4 and
is unused since commit f6d004f7eb5a4d9fbdbb8fef898bef45bd3b4008.
Removed unused function dateSortInverse()

Was introduced in commit 8de0de11fdfae05f37a10e3b40a59b88157e738e and
is unused since commit 178fccaeea5e2c5cacd6f9a300c6a79511c590fa.
Moved categorySort() and dateSort() and annotated them as private
Started documenting javascript functions
Removed unused function getFeedItem()

Was introduced in commit e9cdfeaf84a5861526db9582a0d09eab49856c13 and
is unused since commit 6877b6bbf6bfd455f3890c9ac1ba68ba6e69406c.
Added missing callbacks